Today's Message Index:
----------------------
1. 02:03 AM - Re: Re: Zenith-List: XL grounded in Spain (Iberplanes IGL)
2. 06:33 AM - Re: Re: Zenith-List: XL grounded in Spain (Jim Belcher)
3. 08:46 AM - Re: Zenith-List: XL grounded in Spain (Martin Pohl)
4. 09:02 AM - Re: Zenair Europe's comments on the Dutch accident and grounding (Gig Giacona)
5. 09:11 AM - Re: Re: Zenith-List: XL grounded in Spain (jaybannist@cs.com)
6. 09:40 AM - Re: Zenith-List: XL grounded in Spain (Brady)
7. 10:27 AM - Re: Re: Zenair Europe's comments on the Dutch accident and grounding (David Mikesell)
8. 10:31 AM - Re: Re: Zenith-List: XL grounded in Spain (David Mikesell)
9. 11:18 AM - Re: Re: Zenith-List: XL grounded in Spain (Iberplanes IGL)
10. 11:22 AM - Re: Re: Zenith-List: XL grounded in Spain (Iberplanes IGL)
11. 12:24 PM - Re: Re: Zenair Europe's comments on the Dutch accident and grounding (Paul Mulwitz)
12. 01:57 PM - Re: Re: Zenith-List: XL grounded in Spain (Bryan Martin)
13. 02:22 PM - Re: Re: Zenith-List: XL grounded in Spain (Iberplanes IGL)
14. 02:39 PM - Re: Re: Zenith-List: XL grounded in Spain (Greg Cox, Gas-n-Go Automotive Pty Ltd)
15. 02:42 PM - Re: Re: Zenith-List: XL grounded in Spain (Craig Payne)
16. 02:48 PM - Re: Re: Zenith-List: XL grounded in Spain (Craig Payne)
17. 03:10 PM - Re: Re: Zenith-List: XL grounded in Spain (Jim Belcher)
18. 04:16 PM - Strange goop in the overflow bottle (LarryMcFarland)
19. 05:34 PM - Wing Spars- a comparison(non-scientific) (Dirk Zahtilla)
20. 07:36 PM - Re: Zenith-List: XL grounded in Spain (Brady)
21. 07:37 PM - Re: Strange goop in the overflow bottle (Ron Lendon)
22. 07:42 PM - Re: Re: Zenair Europe's comments on the Dutch accident and grounding (T. Graziano)
23. 07:47 PM - Re: Zenith-List: XL grounded in Spain (Brady)
Message 1
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| Subject: | Re: Zenith-List: XL grounded in Spain |
because the Holland accident, the Zenair Europe representative sent and
email message to the "Yahoo AVIADOR group" saying that the NL-2008-03 also
applies to Spain. What it is strange here is that this type of notifications
should have come from the DGAC and not from the distributor.
This is the original message in spanish:
Hola a todos
Como representante de Zenair Europe, se comunica que hay una directiva de
obligado cumplimiento (NL-2008-003) por la que todos los aviones CH-601 XL
tienen que estar en tierra ,en tanto no se resuelva la investigacion de un
accidente ocurrido en Septiembre.
Desde Zenair Europe se ha mandado una directiva de correccion
(ZE-2008-01),para todos los clientes y usuarios de 601 XL.
Esperando ser de ayuda ,recibir un afectuoso saludo
2008/11/2 Southern Reflections <purplemoon99@bellsouth.net>
> WHY??
>
> ----- Original Message -----
> *From:* Iberplanes IGL <iberplanes@gmail.com>
> *To:* zenith-list@matronics.com ; zenith601-list@matronics.com
> *Sent:* Saturday, November 01, 2008 7:09 PM
> *Subject:* Zenith-List: XL grounded in Spain
>
> Hello friends,
>
> Sorry to inform that the XL are grounded in Spain.
>
> bye,
>
>
> --
> Alberto Martin
> www.iberplanes.es
> Igualada - Barcelona - Spain
>
> ----------------------------------------------
> Zodiac 601 XL Builder
> Serial: 6-7011
>
> Tail Kit: Finished
> Wings: Not Started
> Fuselage: Ordered
> Engine: Jabiru 3300
>
> *
>
> href="http://www.matronics.com/contribution">http://www.matronics.com/chref="http://www.matronics.com/Navigator?Zenith-List">http://www.matronhref="http://forums.matronics.com">http://forums.matronics.com*
>
> *
>
>
--
Alberto Martin
www.iberplanes.es
Igualada - Barcelona - Spain
----------------------------------------------
Zodiac 601 XL Builder
Serial: 6-7011
Tail Kit: Finished
Wings: Not Started
Fuselage: Ordered
Engine: Jabiru 3300
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| Subject: | Re: Zenith-List: XL grounded in Spain |
The Zenair Europe page has links to a number of related items:
http://www.zenairulm.com/News/index_files/Page505.htm
According to one item linked from that page:
"The evolving situation is unfortunately very complex: Because of
multi-lateral agreements between many Civil Aviation Authorities (CAA) in
Europe, when one agency (like the Netherlands) issues an emergency
airworthiness directive, other agencies are tempted to quickly follow suit -
especially when additional information from the original decision makers of
the issuing agency are not readily available.
In the last 24 hours, we have been informed (by Zodiac owners) of two other
countries that have followed the Dutch action, grounding the Zenair CH 601 XL
until further notice: Germany and Sweden. These actions were not taken based
on any new information on the Zodiac design. They were strictly based of the
Dutch AD (NL-2008-003). "
It sounds from this (and other links on the site), that when one European
country knee-jerks, everybody knee-jerks!
=============================================
Those who can, do. Those who can't, sue.
================================================
Jim B. Belcher
BS, MS Physics, math, Computer Science
A&P/IA
Instrument Rated Pilot
General Radio Telephone Certificate
================================================
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| Subject: | Re: Zenith-List: XL grounded in Spain |
The "problem" in Europe is, that normally one CAA issues a "type certificate" for
an aircraft type, whereas other CAAs base their "certificate" on this first
certificate.
As I understand, the XL certificate was first issued in Germany. Therefore I guess
that a major part of the investigation will most probably be performed with
the german CAA.
Martin
--------
Martin Pohl
Zodiac XL QBK
8645 Jona, Switzerland
www.pohltec.ch/ZodiacXL
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=211776#211776
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| Subject: | Re: Zenair Europe's comments on the Dutch accident and |
grounding
I fail to see how not even contacting the designer prior to grounding of the airframe
can be called investigating. I sound reactionary to me.
Everyone I know involved takes it very seriously. And according to what has been
released by Zenith the NTSB is investigating in concert with Zenith.
And there has been quite a bit of information for builders/flyers of the XL to
act on. Namely, the elevator stops and checking to insure that the control cables
are properly tensioned.
skyguynca wrote:
> Really? I like the fact they are really gonna investigate it, not like the
> FAA. The FAA really does not investigate experimental accidents. I have been
> in a few investigations with the FAA and when it is a certified aircraft
> involved they do everything, no stone left unturned. If it is a experimental
> it is a quick once over, pictures and report.
>
> Personally I think the Dutch may find something. Don't' get me wrong I own
> 601 HD HDS and XL plans along with 701 plans and the HD and HDS have never
> had failures like we are seeing in the XL planes whether they are plans
> built, kit built or factory built in Czech. I truly believe that too many
> people are taking the whole 601XL problems personally and refuse to think
> there just might be a problem. So before we condem the Dutch for doing what
> they do every year and been doing it for ever, let them have their vacation
> and then lets see what they come up with.
>
> David M.
>
> --
--------
W.R. "Gig" Giacona
601XL Under Construction
See my progress at www.peoamerica.net/N601WR
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=211782#211782
Message 5
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| Subject: | Re: Zenith-List: XL grounded in Spain |
The real problem is that anyone who builds and flies an experimental airplane
must be mentally retarded to begin with and therefore the State (the EU Nanny
State) must act to protect them from themselves.? There are so few of them around
and they are not politically significant; so stomping on all of them at once
is no big deal.
Jay in Dallas
Do not archive
-----Original Message-----
From: Martin Pohl <mpohl@pohltec.ch>
Sent: Sun, 2 Nov 2008 10:45 am
Subject: Zenith601-List: Re: Zenith-List: XL grounded in Spain
The "problem" in Europe is, that normally one CAA issues a "type certificate"
for an aircraft type, whereas other CAAs base their "certificate" on this first
certificate.
As I understand, the XL certificate was first issued in Germany. Therefore I
guess that a major part of the investigation will most probably be performed
with the german CAA.
Martin
--------
Martin Pohl
Zodiac XL QBK
8645 Jona, Switzerland
www.pohltec.ch/ZodiacXL
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=211776#211776
________________________________________________________________________
Email message sent from CompuServe - visit us today at http://www.cs.com
Message 6
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| Subject: | Re: Zenith-List: XL grounded in Spain |
Have I noticed an interesting trend; or am I wrong?
Are most of these accidents are happening overseas?
I haven't been following this very closely but it seems to me that the Europeans
are having more problems with these planes than we are here.
Does that seem strange to anyone else?
or am I just way off the mark?
How many planes have gone down here in the US?
How many have gone down else where?
How many are flying here?
How many are flying in each of those countries?
I'm just curious.
--------
Brady McCormick
Poulsbo, WA
www.magnificentmachine.com
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=211799#211799
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| Subject: | Re: Zenair Europe's comments on the Dutch accident |
and grounding
OK, now I really don't see how or why they need to contact the designer.
When a factory certified line gets grounded they get notified and that is
all. The investigation needs to remain separate from the designers and
companys to assure a through investigations is done.
Now after reading all these replies don't you guys see how personally you
are taking this whole thing? Your planes are not grounded, your not being
investigated, so why all the commotion and emotions? I could understand if
the FAA grounded all 601XL's in the US but that is not the case.
Try remaining unemotional, non-speculative and just wait for the findings of
the CAA.
David M.
-----Original Message-----
From: owner-zenith601-list-server@matronics.com
[mailto:owner-zenith601-list-server@matronics.com] On Behalf Of Gig Giacona
Sent: Sunday, November 02, 2008 9:02 AM
Subject: Zenith601-List: Re: Zenair Europe's comments on the Dutch accident
and grounding
I fail to see how not even contacting the designer prior to grounding of the
airframe can be called investigating. I sound reactionary to me.
Everyone I know involved takes it very seriously. And according to what has
been released by Zenith the NTSB is investigating in concert with Zenith.
And there has been quite a bit of information for builders/flyers of the XL
to act on. Namely, the elevator stops and checking to insure that the
control cables are properly tensioned.
skyguynca wrote:
> Really? I like the fact they are really gonna investigate it, not like the
> FAA. The FAA really does not investigate experimental accidents. I have
been
> in a few investigations with the FAA and when it is a certified aircraft
> involved they do everything, no stone left unturned. If it is a
experimental
> it is a quick once over, pictures and report.
>
> Personally I think the Dutch may find something. Don't' get me wrong I own
> 601 HD HDS and XL plans along with 701 plans and the HD and HDS have never
> had failures like we are seeing in the XL planes whether they are plans
> built, kit built or factory built in Czech. I truly believe that too many
> people are taking the whole 601XL problems personally and refuse to think
> there just might be a problem. So before we condem the Dutch for doing
what
> they do every year and been doing it for ever, let them have their
vacation
> and then lets see what they come up with.
>
> David M.
>
> --
--------
W.R. "Gig" Giacona
601XL Under Construction
See my progress at www.peoamerica.net/N601WR
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=211782#211782
Message 8
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| Subject: | Re: Zenith-List: XL grounded in Spain |
NO, there have been 8 in the US and if you search the archives you will see
tons of emotional replies and speculations.
As I have stated in every reply, JUST WAIT AND LET THE INVESTIGATORS DO
THEIR JOBS.
David M.
-----Original Message-----
From: owner-zenith601-list-server@matronics.com
[mailto:owner-zenith601-list-server@matronics.com] On Behalf Of Brady
Sent: Sunday, November 02, 2008 9:40 AM
Subject: Zenith601-List: Re: Zenith-List: XL grounded in Spain
Have I noticed an interesting trend; or am I wrong?
Are most of these accidents are happening overseas?
I haven't been following this very closely but it seems to me that the
Europeans are having more problems with these planes than we are here.
Does that seem strange to anyone else?
or am I just way off the mark?
How many planes have gone down here in the US?
How many have gone down else where?
How many are flying here?
How many are flying in each of those countries?
I'm just curious.
--------
Brady McCormick
Poulsbo, WA
www.magnificentmachine.com
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=211799#211799
Message 9
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| Subject: | Re: Zenith-List: XL grounded in Spain |
*"that when one European country knee-jerks, everybody knee-jerks!" *
With all due respect that why this called *"EUROPEAN UNION" *
2008/11/2 Jim Belcher <z601@anemicaardvark.com>
> >
>
> The Zenair Europe page has links to a number of related items:
>
> http://www.zenairulm.com/News/index_files/Page505.htm
>
> According to one item linked from that page:
>
> "The evolving situation is unfortunately very complex: Because of
> multi-lateral agreements between many Civil Aviation Authorities (CAA) in
> Europe, when one agency (like the Netherlands') issues an "emergency
> airworthiness directive", other agencies are tempted to quickly follow suit
> -
> especially when additional information from the original decision makers of
> the issuing agency are not readily available.
>
>
> In the last 24 hours, we have been informed (by Zodiac owners) of two other
> countries that have followed the Dutch action, grounding the Zenair CH 601
> XL
> until further notice: Germany and Sweden. These actions were not taken
> based
> on any new information on the Zodiac design. They were strictly based of
> the
> Dutch AD (NL-2008-003). "
>
> It sounds from this (and other links on the site), that when one European
> country knee-jerks, everybody knee-jerks!
> =============================================
> Those who can, do. Those who can't, sue.
> ================================================
> Jim B. Belcher
> BS, MS Physics, math, Computer Science
> A&P/IA
> Instrument Rated Pilot
> General Radio Telephone Certificate
> ================================================
>
>
--
Alberto Martin
www.iberplanes.es
Igualada - Barcelona - Spain
----------------------------------------------
Zodiac 601 XL Builder
Serial: 6-7011
Tail Kit: Finished
Wings: Not Started
Fuselage: Ordered
Engine: Jabiru 3300
Message 10
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| Subject: | Re: Zenith-List: XL grounded in Spain |
Brady,
ZBAG has 7 XL cases on its DB, they are all spread among countries, and for
your information USA has 3 of the 7 accidents.
bye.
2008/11/2 Brady <brady@magnificentmachine.com>
> brady@magnificentmachine.com>
>
> Have I noticed an interesting trend; or am I wrong?
> Are most of these accidents are happening overseas?
> I haven't been following this very closely but it seems to me that the
> Europeans are having more problems with these planes than we are here.
> Does that seem strange to anyone else?
> or am I just way off the mark?
>
> How many planes have gone down here in the US?
> How many have gone down else where?
> How many are flying here?
> How many are flying in each of those countries?
>
> I'm just curious.
>
> --------
> Brady McCormick
> Poulsbo, WA
> www.magnificentmachine.com
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=211799#211799
>
>
--
Alberto Martin
www.iberplanes.es
Igualada - Barcelona - Spain
----------------------------------------------
Zodiac 601 XL Builder
Serial: 6-7011
Tail Kit: Finished
Wings: Not Started
Fuselage: Ordered
Engine: Jabiru 3300
Message 11
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| Subject: | Re: Zenair Europe's comments on the Dutch accident |
and grounding
Hi David,
Let me take a try at answering your question.
I did my best to research and determine the best kit plane I could
find when I decided I wanted to build one. I wanted a stable design
that had a good reputation for safety and other qualities that also
met the LSA limits. I particularly wanted a plane designed by a
talented and accomplished designer. I determined the Zodiac XL met
all my criteria nicely.
After working on my XL kit for a year or so, I learned the design was
indeed not at all stable. It was being changed on a nearly daily
basis. The changes were being made by apparently inexperienced
engineers who didn't know or care about the design principles held by
the original designer - things like no solid rivets being used. They
were trying to meet the new consensus standard for LSA which was
still evolving when I thought the design was stable.
Then the XLs started falling out of the sky for no apparent
reason. In two years I heard of 4 different planes that suffered
wing separations in what seemed like gentle flight - straight and
level at apparently pattern speeds or normal cruise speeds. This led
to numerous speculations by both qualified and unqualified people
about why the failures had occurred and included at least one
complete NTSB investigation that resulted in a worthless report.
So I, for one, am frustrated about the question of whether or not
there is a fatal design flaw in the XL. It seems there is enough
smoke to indicate a real fire, but nobody seems to be able to pin the
problem down.
Now along comes a government engineer who announces he has found a
fatal load bearing flaw in the XL design and then immediately goes on
extended vacation so nobody can discuss it with him. The XL gets
grounded in several countries. I figure we have one of two
cases. The Dutch engineer was mistaken and no flaw was really found
or indeed a real flaw was found but not announced to the world. In
either case I anxiously await the results of this event.
I suppose there are other builders nearing first flight or already
flying who would really like for this question to get a final
resolution. Hopefully, a design fix that actually fixes the problem
will also be forthcoming.
So yes, I am taking this event a little personally. I make no
apology for this reaction.
Best regards,
Paul
XL getting close
At 10:25 AM 11/2/2008, you wrote:
>Now after reading all these replies don't you guys see how personally you
>are taking this whole thing? Your planes are not grounded, your not being
>investigated, so why all the commotion and emotions? I could understand if
>the FAA grounded all 601XL's in the US but that is not the case.
>
>Try remaining unemotional, non-speculative and just wait for the findings of
>the CAA.
>
>
>David M.
Message 12
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| Subject: | Re: Zenith-List: XL grounded in Spain |
There are 213 601XLs listed in the FAA database, they might not all be
completed and flying though. There may be others that are not listed
with that particular model designation since, in the US, a homebuilt
can be given literally any model designation the builder chooses.
There have been four accidents in the US involving wing failure:
2/8/2006, Oakdale, CA , Hooker Zodiac 601XL, N105RH, Fatal(2), NTSB
Identification: LAX06LA105
11/4/2006, Yuba City, CA , Aircraft Mfg & Dev. Co. (AMD) CH601XL
SLSA, N158MD, Fatal(2), NTSB Identification: LAX07FA026
5/2/2007, Canadian, TX. Walker Zenith Zodiac 601 XL, N10028,
Fatal(1), NTSB Identification: DFW07LA102
4/7/2008, Polk City, FL, Czech Aircraft Works SPOL SRO CH 601 XL
RTF, N357DT, Fatal(1), NTSB Identification: NYC08FA158
N10028 broke up in flight soon after the sport pilot owner took off
with low ceilings and poor visibility with a thunderstorm in the
vicinity. The other three accidents don't seem to have any such
obvious contributing factors. One was closed out as unexplained
structural failure, two are still under investigation. Of the three
unexplained accidents, one was a homebuilt, one was an factory built
AMD LSA and the other was a Czech built ELSA.
Go to http://www.ntsb.gov/ntsb/query.asp and plug in the NTSB ID
number for details.
There was a recent accident in France of an unauthorized Polish copy
of a Zenith 601XL. The crew survived that one with the help of a
ballistic parachute. The cause of that one was determined by
government investigators as wing failure due to pilot maneuvers
exceeding the aircraft structural limits.
There was a crash near Barcelona Spain and the most recent one in the
Netherlands.
On Nov 2, 2008, at 2:22 PM, Iberplanes IGL wrote:
> Brady,
>
> ZBAG has 7 XL cases on its DB, they are all spread among countries,
> and for your information USA has 3 of the 7 accidents.
>
> bye.
>
>
> 2008/11/2 Brady <brady@magnificentmachine.com>
> >
>
> Have I noticed an interesting trend; or am I wrong?
> Are most of these accidents are happening overseas?
> I haven't been following this very closely but it seems to me that
> the Europeans are having more problems with these planes than we are
> here.
> Does that seem strange to anyone else?
> or am I just way off the mark?
>
> How many planes have gone down here in the US?
> How many have gone down else where?
> How many are flying here?
> How many are flying in each of those countries?
>
> I'm just curious.
>
--
Bryan Martin
N61BM, CH 601 XL,
RAM Subaru, Stratus redrive.
Message 13
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| Subject: | Re: Zenith-List: XL grounded in Spain |
you forgot.....
1) XL down in Barcelona, 2 death.
2) XL down in Brazil, 2 death
3) XL down in Australia, 2 death
4I) XL down in Holland, 2 death....
all this year
2008/11/2 Bryan Martin <bryanmmartin@comcast.net>
> There are 213 601XLs listed in the FAA database, they might not all be
> completed and flying though. There may be others that are not listed with
> that particular model designation since, in the US, a homebuilt can be given
> literally any model designation the builder chooses.
>
> There have been four accidents in the US involving wing failure:
>
> 2/8/2006, Oakdale, CA , Hooker Zodiac 601XL, N105RH, Fatal(2), NTSB
> Identification: LAX06LA105
>
> 11/4/2006, Yuba City, CA , Aircraft Mfg & Dev. Co. (AMD) CH601XL SLSA,
> N158MD, Fatal(2), NTSB Identification: LAX07FA026
>
> 5/2/2007, Canadian, TX. Walker Zenith Zodiac 601 XL, N10028,
> Fatal(1), NTSB Identification: DFW07LA102
>
> 4/7/2008, Polk City, FL, Czech Aircraft Works SPOL SRO CH 601 XL RTF,
> N357DT, Fatal(1), NTSB Identification: NYC08FA158
>
> N10028 broke up in flight soon after the sport pilot owner took off with
> low ceilings and poor visibility with a thunderstorm in the vicinity. The
> other three accidents don't seem to have any such obvious contributing
> factors. One was closed out as unexplained structural failure, two are still
> under investigation. Of the three unexplained accidents, one was a
> homebuilt, one was an factory built AMD LSA and the other was a Czech built
> ELSA.
>
> Go to http://www.ntsb.gov/ntsb/query.asp and plug in the NTSB ID number
> for details.
>
> There was a recent accident in France of an unauthorized Polish copy of a
> Zenith 601XL. The crew survived that one with the help of
> a ballistic parachute. The cause of that one was determined by government
> investigators as wing failure due to pilot maneuvers exceeding the aircraft
> structural limits.
>
> There was a crash near Barcelona Spain and the most recent one in the
> Netherlands.
>
> On Nov 2, 2008, at 2:22 PM, Iberplanes IGL wrote:
>
>
> Brady,
>
> ZBAG has 7 XL cases on its DB, they are all spread among countries, and
> for your information USA has 3 of the 7 accidents.
>
> bye.
>
>
> 2008/11/2 Brady <brady@magnificentmachine.com>
>
>> brady@magnificentmachine.com>
>>
>> Have I noticed an interesting trend; or am I wrong?
>> Are most of these accidents are happening overseas?
>> I haven't been following this very closely but it seems to me that the
>> Europeans are having more problems with these planes than we are here.
>> Does that seem strange to anyone else?
>> or am I just way off the mark?
>>
>> How many planes have gone down here in the US?
>> How many have gone down else where?
>> How many are flying here?
>> How many are flying in each of those countries?
>>
>> I'm just curious.
>>
>>
>
> --
> Bryan Martin
> N61BM, CH 601 XL,
> RAM Subaru, Stratus redrive.
>
>
> *
>
>
--
Alberto Martin
www.iberplanes.es
Igualada - Barcelona - Spain
----------------------------------------------
Zodiac 601 XL Builder
Serial: 6-7011
Tail Kit: Finished
Wings: Not Started
Fuselage: Ordered
Engine: Jabiru 3300
Message 14
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| Subject: | Re: Zenith-List: XL grounded in Spain |
One thing we do know is that the accident in Australia is not as a result on
structural failure and it is suspected that pilot incapacitation may be the
cause.
The aircraft impacted the ground intact and under power.
Regards,
Greg
From: owner-zenith601-list-server@matronics.com
[mailto:owner-zenith601-list-server@matronics.com] On Behalf Of Iberplanes
IGL
Sent: Monday, 3 November 2008 9:22 AM
Subject: Re: Zenith601-List: Re: Zenith-List: XL grounded in Spain
you forgot.....
1) XL down in Barcelona, 2 death.
2) XL down in Brazil, 2 death
3) XL down in Australia, 2 death
4I) XL down in Holland, 2 death....
all this year
2008/11/2 Bryan Martin <bryanmmartin@comcast.net>
There are 213 601XLs listed in the FAA database, they might not all be
completed and flying though. There may be others that are not listed with
that particular model designation since, in the US, a homebuilt can be given
literally any model designation the builder chooses.
There have been four accidents in the US involving wing failure:
2/8/2006, Oakdale, CA , Hooker Zodiac 601XL, N105RH, Fatal(2), NTSB
Identification: LAX06LA105
11/4/2006, Yuba City, CA , Aircraft Mfg & Dev. Co. (AMD) CH601XL SLSA,
N158MD, Fatal(2), NTSB Identification: LAX07FA026
5/2/2007, Canadian, TX. Walker Zenith Zodiac 601 XL, N10028, Fatal(1),
NTSB Identification: DFW07LA102
4/7/2008, Polk City, FL, Czech Aircraft Works SPOL SRO CH 601 XL RTF,
N357DT, Fatal(1), NTSB Identification: NYC08FA158
N10028 broke up in flight soon after the sport pilot owner took off with low
ceilings and poor visibility with a thunderstorm in the vicinity. The other
three accidents don't seem to have any such obvious contributing factors.
One was closed out as unexplained structural failure, two are still under
investigation. Of the three unexplained accidents, one was a homebuilt, one
was an factory built AMD LSA and the other was a Czech built ELSA.
Go to http://www.ntsb.gov/ntsb/query.asp and plug in the NTSB ID number for
details.
There was a recent accident in France of an unauthorized Polish copy of a
Zenith 601XL. The crew survived that one with the help of a ballistic
parachute. The cause of that one was determined by government investigators
as wing failure due to pilot maneuvers exceeding the aircraft structural
limits.
There was a crash near Barcelona Spain and the most recent one in the
Netherlands.
On Nov 2, 2008, at 2:22 PM, Iberplanes IGL wrote:
Brady,
ZBAG has 7 XL cases on its DB, they are all spread among countries, and for
your information USA has 3 of the 7 accidents.
bye.
2008/11/2 Brady <brady@magnificentmachine.com>
Have I noticed an interesting trend; or am I wrong?
Are most of these accidents are happening overseas?
I haven't been following this very closely but it seems to me that the
Europeans are having more problems with these planes than we are here.
Does that seem strange to anyone else?
or am I just way off the mark?
How many planes have gone down here in the US?
How many have gone down else where?
How many are flying here?
How many are flying in each of those countries?
I'm just curious.
--
Bryan Martin
N61BM, CH 601 XL,
RAM Subaru, Stratus redrive.
--
Alberto Martin
www.iberplanes.es
Igualada - Barcelona - Spain
----------------------------------------------
Zodiac 601 XL Builder
Serial: 6-7011
Tail Kit: Finished
Wings: Not Started
Fuselage: Ordered
Engine: Jabiru 3300
Message 15
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| Subject: | Re: Zenith-List: XL grounded in Spain |
"There are 213 601XLs listed in the FAA database"
There is no real way of knowing exactly how many XLs are in the FAA
database. I can build an XL from scratch or kit and register it as a 601 (no
XL) or "magic carpet special". In fact someone recommended doing just this a
while ago as a way of preventing state sales tax offices from accurately
valuing the plane.
-- Craig
From: owner-zenith601-list-server@matronics.com
[mailto:owner-zenith601-list-server@matronics.com] On Behalf Of Bryan Martin
Sent: Sunday, November 02, 2008 2:57 PM
Subject: Re: Zenith601-List: Re: Zenith-List: XL grounded in Spain
There are 213 601XLs listed in the FAA database, they might not all be
completed and flying though. There may be others that are not listed with
that particular model designation since, in the US, a homebuilt can be given
literally any model designation the builder chooses.
There have been four accidents in the US involving wing failure:
2/8/2006, Oakdale, CA , Hooker Zodiac 601XL, N105RH, Fatal(2), NTSB
Identification: LAX06LA105
11/4/2006, Yuba City, CA , Aircraft Mfg & Dev. Co. (AMD) CH601XL SLSA,
N158MD, Fatal(2), NTSB Identification: LAX07FA026
5/2/2007, Canadian, TX. Walker Zenith Zodiac 601 XL, N10028, Fatal(1),
NTSB Identification: DFW07LA102
4/7/2008, Polk City, FL, Czech Aircraft Works SPOL SRO CH 601 XL RTF,
N357DT, Fatal(1), NTSB Identification: NYC08FA158
N10028 broke up in flight soon after the sport pilot owner took off with low
ceilings and poor visibility with a thunderstorm in the vicinity. The other
three accidents don't seem to have any such obvious contributing factors.
One was closed out as unexplained structural failure, two are still under
investigation. Of the three unexplained accidents, one was a homebuilt, one
was an factory built AMD LSA and the other was a Czech built ELSA.
Go to http://www.ntsb.gov/ntsb/query.asp and plug in the NTSB ID number for
details.
There was a recent accident in France of an unauthorized Polish copy of a
Zenith 601XL. The crew survived that one with the help of a ballistic
parachute. The cause of that one was determined by government investigators
as wing failure due to pilot maneuvers exceeding the aircraft structural
limits.
There was a crash near Barcelona Spain and the most recent one in the
Netherlands.
On Nov 2, 2008, at 2:22 PM, Iberplanes IGL wrote:
Brady,
ZBAG has 7 XL cases on its DB, they are all spread among countries, and for
your information USA has 3 of the 7 accidents.
bye.
2008/11/2 Brady <brady@magnificentmachine.com>
Have I noticed an interesting trend; or am I wrong?
Are most of these accidents are happening overseas?
I haven't been following this very closely but it seems to me that the
Europeans are having more problems with these planes than we are here.
Does that seem strange to anyone else?
or am I just way off the mark?
How many planes have gone down here in the US?
How many have gone down else where?
How many are flying here?
How many are flying in each of those countries?
I'm just curious.
--
Bryan Martin
N61BM, CH 601 XL,
RAM Subaru, Stratus redrive.
Message 16
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| Subject: | Re: Zenith-List: XL grounded in Spain |
Also some sort of bird-strike or canopy mishap was suspected since pieces of
canopy were found a great distance (one or two miles?) from the water
impact.
-- Craig
From: owner-zenith601-list-server@matronics.com
[mailto:owner-zenith601-list-server@matronics.com] On Behalf Of Greg Cox,
Gas-n-Go Automotive Pty Ltd
Sent: Sunday, November 02, 2008 3:39 PM
Subject: RE: Zenith601-List: Re: Zenith-List: XL grounded in Spain
One thing we do know is that the accident in Australia is not as a result on
structural failure and it is suspected that pilot incapacitation may be the
cause.
The aircraft impacted the ground intact and under power.
Regards,
Greg
From: owner-zenith601-list-server@matronics.com
[mailto:owner-zenith601-list-server@matronics.com] On Behalf Of Iberplanes
IGL
Sent: Monday, 3 November 2008 9:22 AM
Subject: Re: Zenith601-List: Re: Zenith-List: XL grounded in Spain
you forgot.....
1) XL down in Barcelona, 2 death.
2) XL down in Brazil, 2 death
3) XL down in Australia, 2 death
4I) XL down in Holland, 2 death....
all this year
2008/11/2 Bryan Martin <bryanmmartin@comcast.net>
There are 213 601XLs listed in the FAA database, they might not all be
completed and flying though. There may be others that are not listed with
that particular model designation since, in the US, a homebuilt can be given
literally any model designation the builder chooses.
There have been four accidents in the US involving wing failure:
2/8/2006, Oakdale, CA , Hooker Zodiac 601XL, N105RH, Fatal(2), NTSB
Identification: LAX06LA105
11/4/2006, Yuba City, CA , Aircraft Mfg & Dev. Co. (AMD) CH601XL SLSA,
N158MD, Fatal(2), NTSB Identification: LAX07FA026
5/2/2007, Canadian, TX. Walker Zenith Zodiac 601 XL, N10028, Fatal(1),
NTSB Identification: DFW07LA102
4/7/2008, Polk City, FL, Czech Aircraft Works SPOL SRO CH 601 XL RTF,
N357DT, Fatal(1), NTSB Identification: NYC08FA158
N10028 broke up in flight soon after the sport pilot owner took off with low
ceilings and poor visibility with a thunderstorm in the vicinity. The other
three accidents don't seem to have any such obvious contributing factors.
One was closed out as unexplained structural failure, two are still under
investigation. Of the three unexplained accidents, one was a homebuilt, one
was an factory built AMD LSA and the other was a Czech built ELSA.
Go to http://www.ntsb.gov/ntsb/query.asp and plug in the NTSB ID number for
details.
There was a recent accident in France of an unauthorized Polish copy of a
Zenith 601XL. The crew survived that one with the help of a ballistic
parachute. The cause of that one was determined by government investigators
as wing failure due to pilot maneuvers exceeding the aircraft structural
limits.
There was a crash near Barcelona Spain and the most recent one in the
Netherlands.
On Nov 2, 2008, at 2:22 PM, Iberplanes IGL wrote:
Brady,
ZBAG has 7 XL cases on its DB, they are all spread among countries, and for
your information USA has 3 of the 7 accidents.
bye.
2008/11/2 Brady <brady@magnificentmachine.com>
Have I noticed an interesting trend; or am I wrong?
Are most of these accidents are happening overseas?
I haven't been following this very closely but it seems to me that the
Europeans are having more problems with these planes than we are here.
Does that seem strange to anyone else?
or am I just way off the mark?
How many planes have gone down here in the US?
How many have gone down else where?
How many are flying here?
How many are flying in each of those countries?
I'm just curious.
--
Bryan Martin
N61BM, CH 601 XL,
RAM Subaru, Stratus redrive.
--
Alberto Martin
www.iberplanes.es
Igualada - Barcelona - Spain
----------------------------------------------
Zodiac 601 XL Builder
Serial: 6-7011
Tail Kit: Finished
Wings: Not Started
Fuselage: Ordered
Engine: Jabiru 3300
http://www.matronics.com/contribution
http://www.matronics.com/Navigator?Zenith601-List
http://forums.matronics.com
Message 17
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| Subject: | Re: Zenith-List: XL grounded in Spain |
On Sunday 02 November 2008 16:41, Craig Payne wrote:
> There is no real way of knowing exactly how many XLs are in the FAA
> database. I can build an XL from scratch or kit and register it as a 601
> (no XL) or "magic carpet special". In fact someone recommended doing just
> this a while ago as a way of preventing state sales tax offices from
> accurately valuing the plane.
A good point, which works both for and against us. Experimental 601XL
derivatives can be listed as anything you choose, while the factory built XLs
will show up as XLs.
Because the experimentals can be listed by your choice of name, and there can
be wide variations in how an experimental aircraft is built, it is hard to
draw too many conclusions. But it also makes it hard to ground all
experimentals which may be of the same general type, in the U.S.
I'm beginning to think I'll find the simplest, cheapest experimental I can
find, even if nobody has built one in years, and list my aircraft under that
type.
--
=============================================
Those who can, do. Those who can't, sue.
================================================
Jim B. Belcher
BS, MS Physics, math, Computer Science
A&P/IA
Instrument Rated Pilot
General Radio Telephone Certificate
================================================
Message 18
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| Subject: | Strange goop in the overflow bottle |
Hi Guys,
This week begins the Annual Inspection of my 601HDS and one of the first
things was a coolant leak that dripped ever so slightly from the coolant
overflow bottle. Large filler hoses were moved out of the way. I tried
to siphon the last half-inch of coolant, but goop on the bottom
prevented it. The coolant bottle was removed and the last half-pint of
coolant was poured into another bottle. The bottom goop was very
different from the clean and transparent coolant. It was gray-black and
didnt act or feel like oil. After flushing the goop out of the bottle
in two level chunks, I put the goop on paper and it dried to a
gray-black cake. Rubbed between the fingers, it felt like an extremely
fine compound. The bottle was refilled and set on a shelf to check it
again for leakage. There was a leak spot on the back firewall side where
the bottle contacts a rivet head. I've another bottle to install but was
very curious about the accumulated 1/8-inch of goop on the bottom of the
coolant bottle. Any ideas of what it might be? I've never encountered
this before. It's not oil, nor does it leave a carbon trace on the
fingers. It washes off like regular soil. Volume was 1/8 x 2 x 3 lg. The
coolant bottle has never been changed or cleaned, but my coolant has
been changed twice at 60 hours. Any ideas?
Thank you for your response,
Larry McFarland 601HDS at www.macsmachine.com
Message 19
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| Subject: | Wing Spars- a comparison(non-scientific) |
I have borrowed a set of drawings for the RV-6 and compared the wing
spar construction. Yes I know the RV is heavier etc., but... the wing
spars in the RV: 1. meet at the center of the fuselage
2. .040" main spar web and .040" doubler(spaced to form a box type spar)
70" from center of fuse outward
3. spars boxed in w/ .040" (601 is .032")
4. spars held together w/ 1/4"x12"4130 steel plates w/5bolts ea.side,
top & bot. etc.
This is just a cursory comparison but seeing the differences really was
an eye opener for me.
I suspect this design is less than 10 lbs. extra but sometimes it's
worth it to have extra weight. I think sometimes we sacrifice our safety
just trying to lighten our planes to the extreem.
I don't know where to go with this... I wouldn't feel comfortable making
changes to the 601 design since I'm not qualified, but???
Dirk
Message 20
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| Subject: | Re: Zenith-List: XL grounded in Spain |
OK;
I seemed to have touched a few nerves.
First Let me apologize and say that I was not insinuating anything and that I was
just asking questions.
I am not trying to start anything.
I don't have any theories.
--------
Brady McCormick
Poulsbo, WA
www.magnificentmachine.com
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=211907#211907
Message 21
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| Subject: | Re: Strange goop in the overflow bottle |
Larry,
We Ionize the water in production at GM to eliminate electrolysis. That or a chemical
reaction between the aluminum and the coolant itself can cause erosion
of the aluminum. It sounds like it might be that type of a thing or its getting
dirt from somewhere. If coolant can get out dirt can get in.
--------
Ron Lendon, Clinton Township, MI
Corvair Zodiac XL, ScrapBuilder ;-)
http://www.mykitlog.com/rlendon
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=211908#211908
Message 22
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| Subject: | Re: Zenair Europe's comments on the Dutch accident |
and grounding
I opened the The UK LAA view on the Dutch XL
sites given by Mr. Dilks and sent them to the zenith 60l matronics list on
30 Oct. I do not believe the msg was received so I am sending again for
those who have not opened the links and read
--------------------------------------------
Copied and pasted below, the link info given by Mr.Dilks - Good reading, in
my opinion for all.
Zenair CH601-XL
The Dutch Civil Aviation Authority has this week issued a directive which
grounds the Zenair CH601-XL in Holland, following reports of a number of
in-flight wing failures with the type.
Our Airworthiness team are currently working to establish how the version of
the CH601-XL previously operating in Holland compares with the version
approved in the UK and to obtain details of the accidents. We have advised
our own CAA that as far we are concerned there is no evidence at present to
ground the type in the UK.
For the time being the LAA stance on the issue is that:
1.. 1.
The Zenair CH601-XL model as cleared by the LAA in the UK has been shown to
meet normal category (i.e. as opposed to aerobatic) airframe strength
requirements both by calculation and by load testing which provides proof of
the integrity of the airframe.
1.. 2.
In common with many other sports aircraft, the CH601-XL exhibits relatively
light 'stick force per g'. The stick forces needed to pitch the aircraft are
not great, albeit in excess of the normal certification minimum values
providing the aircraft is correctly loaded within the allowable cg range.
1.. 3.
In addition, the aircraft has a relatively wide speed range (cruise speed
three times the stall speed) which means that it might be tempting to
operate it at airspeeds above Va where excessive pitch control inputs could
generate sufficient forces in the wings and other airframe parts to cause
structural damage or failure. Strong turbulence must also be avoided at
airspeeds above Vno, the normal operating limit, as this also could result
in structural damage or break-up.
1.. 4.
Loading the aircraft outside of the permitted aft cg limit, e.g. by carrying
too much weight in the cockpit or in the rear baggage compartment, would
further reduce the stick force per g and so make the aircraft more sensitive
in pitch and more easily over-stressed.
5.
Due to the above it is essential that pilots understand and observe the
speed and manoeuvre envelope of the aircraft, and to operate only within the
permitted weight and cg limits. As with most high-performance kitplanes,
'banking and yanking' at airspeeds above the manoeuvring speed could easily
lead to structural failure.
For more details on the subject of structural limitations and the need to
observe structural and weight and balance limits please refer to the article
on the subject by Francis Donaldson in Light Aviation magazine's
'Engineering Matters' supplement of September 2008, or talk to your local
LAA coach.
Zenair Europe has recently issued advice in their AD ZE-2008-01 (available
from www.zenairulm.com/Home) advising owners to check control system cable
tensions before further flight. We are not mandating this action at the
current time, but consider it appropriate advice for owners to follow.
Further updates on the situation will appear on the LAA website and
registered owners of CH601-XL aircraft will be contacted individually as and
when specific instructions become available.
LAA Engineering
30 October 2008
Reprinted from Engineering Matters Volume 1 Issue 9
September 2008
HOW EASY IS IT TO CAUSE STRESS?
We understand stall speeds, but what of cruise speeds and the effects of
turbulence and over-exuberant control inputs?
Two young student pilots were propping up the clubhouse bar, pondering over
a question in a sample PPL airframes paper they had both being doing to
while away the time, their flying slots having been cancelled due to the
weather turning sour a couple of hours previously. The question was over how
strong an aircraft had to be to cope with 'g' loads in flight. Casting his
mind back to school physics lessons and a dimly remembered Newton's laws,
one hazarded: 'If the total weight of the Cessna including fuel, crew and
baggage is 1500 pounds, then if it has to cope with a 4g acceleration then
the wings have to carry four times 1500 pounds i.e. 6000 pounds, right ? So
I guess we tick box A?'
The other, who had spent the morning with his nose buried in a dog-eared
copy of the club's Airframes and Engines text book, rejoined - 'Yes, but
you've
forgotten the safety factor. Aeroplanes have to be able to carry at least
50% more load than the pilot might want to use, to give an extra margin of
safety. That means your Cessna's wings have to be good for an extra 3000
pounds, giving a total of 9000 Lbs. So tick multiple choice box B'.
The two pilots marvelled over the fact that by their reckoning their humble
club Cessna, which weighed less than an old-style Issigonis Mini, had to be
able to carry the weight of two transit vans. 'It just shows', said one,
'how enormously strong these aeroplanes are and how hard pushed you'd have
to be break one in flight'.
'Not so fast, young man' rejoined the grizzled CFI, who, sunk deeply into a
barely-recognisable armchair in another corner of the clubroom, had been
gloomily working out the effect on the club's turnover of yet another
weekend of cancelled lessons. It really had been a terrible summer. 'First
of all, that extra 50% safety factor wasn't put there for the likes of you
two to play with, once you start going into that territory then you're going
to be damaging my aeroplane for sure, even if the wings do stay attached -
which is doubtful. You'll be coming back with the whole airframe
overstressed and only fit for scrap. Even if there are no obvious external
signs like puckered skins or bent wing spars, carrying on flying an
aeroplane that has been overstressed means it may collapse later when some
other poor mutt is flying it.'
'And another thing, most of our 'planes have been around longer than you two
lads, and have been slogging the circuit for decades - much longer than the
designer probably had in mind when he drew up the thing - been repaired a
few times too, if you care to have a look in their logbooks over there...
riveted joints are prone to corrosion you know... despite the best efforts
of our maintenance chaps, these airframes can't be as strong as the day they
left the factory. That's part of the reason airframes are designed with the
extra 50 % safety factor - to allow for degradation in service. And of
course, designers like to have the factor there to give a little leeway in
case they have made a mistake or two in their calculations - slide rule
slipped, or they multiplied by 'pie' instead of 'alpha', too busy thinking
about lunch...!'
'Six thousand pounds sounds like a lot of load to put on a little
aeroplane's
wings, and it is - three tons give or take a bit.. Not bad considering each
of a Cessna's wings only weighs a hundred pound or so, which just shows what
efficient structures they are...have to be, if you built 'em like the Forth
Bridge you'd never get off the ground. Aeronautical engineers have to pare
off every bit of unnecessary weight. If weight wasn't a consideration, the
safety factors
would be much higher, like in most other industries. Ironic isn't it, that
in an aircraft, where collapse of the structure almost inevitably has fatal
consequences, we have lower safety factors than in ground-based vehicles
where failure would most likely just mean having to take the bus home?'
'How easy is it to overstress them? Well, you know there's an interesting
little fact buried in the design rules that apply to almost all light
aeroplanes, microlights and gliders, which is that the backward force the
pilot would have to apply on the control stick grip in flight, to make the
aeroplane reach the 'g' load where it starts to suffer structural damage,
must not be less than fifteen pounds. This is intended to ensure that pilots
can't overstress aeroplanes inadvertently. But think about it, fifteen
pounds is a force so low that you can just about hold it with your little
finger - you can manage more if you are in training from carrying the
dratted plastic bags of shopping away from the supermarket. So only the
force of one little finger may stand between you and a bent aeroplane..'
The students were deflated. Surely, even taking into account all this, 4g
was a lot, much more than you ever need in a simple Cessna. Surely there was
no reason to worry about it providing you just flew normally - after all,
these aren't aerobatic 'planes.
THE STALL TO CRUISE SPEED RATIO AND ITS POTENTIAL EFFECT ON STRUCTURAL
INTEGRITY
Behind the storyline above lurk some really important issues, and dangers
that are becoming increasingly important with the newer, faster breed of
microlight and VLA aircraft and the more challenging types of flying now
regularly being undertaken. Faster speeds bring more potential for high 'g'
problems. To calculate the 'g' that can be pulled inadvertently in an
aeroplane, divide the speed the aircraft is flying at by the aircraft's
stall speed in that configuration and then square the result - so flying at
twice the stall speed means you might pull four 'g', four times the stall
speed equates to a mind-numbing 16g. Whereas the older types of traditional
homebuilt such as Luton Minors and Currie Wots had a relatively slow cruise
speed of barely twice the stall speed, and were therefore largely proof
against being overstressed in flight, today's machines such as the RV range,
Europa and so on have the capability of cruising at more than three times
the stall speed and could therefore relatively easily be overstressed in
flight - flying at three times the stall speed means that up to 9g might be
reached with too much 'back stick'. If the airframe is only designed to cope
with 4g then it will most likely not survive.
VA - MANOUEVRING SPEED
To stay out of trouble with the airframe, you have to fly with three safety
speeds in mind. The manoeuvring speed Va (pronounced 'vee-aye') is the
maximum airspeed you can fly without risking structural damage if you carry
out abrupt manoeuvres. Confusingly, that's not to say you mustn't manoeuvre
at speeds above Va, it simply means that if you do then you must be careful
not to pull too much 'g', to avoid overstressing the aeroplane. If you fly
at less than Va then no matter how much you pull (or, for that matter, push)
on the stick, the aeroplane will stall before it reaches the maximum
manoeuvring 'g' which it has been designed to carry. You'll almost
invariably find Va quoted in the aeroplane's flight manual in the
'limitations' section, on the Permit to Fly or in the manufacturer's data.
Sometimes this speed is referred to as 'maximum speed for full control
deflection'..this is a bit misleading because it rather implies that if you
fly at a speed a bit above Va then you will be OK providing you use a bit
less than full deflection, which is not necessarily the case. Depending on
the stability and control power of the aeroplane, and in particular its
centre of gravity position and trim setting, it may be possible to reach
high g levels without the stick being far from neutral. In an unstable
aeroplane, you might even find that the stick has to go forward of neutral
just to stop a steep turn 'tightening up' on you. Not that PPLs normally get
a chance to fly such unstable aeroplanes - but it can happen, especially on
older types, or if they are mis-loaded with an extreme aft cg.
When flying at speeds above Va, the risk of overstress and structural
failure is there, whatever reason you manoeuvre. Not all manoeuvres are
planned, and it may be the spontaneous response to some external cause which
leads you into danger - for example the Zenair pilot who was flying a low
pass over a farm strip at high speed when he spotted wires close ahead,
pulled up sharply to clear the wires - and caused a structural failure of
his wing attachments, with consequences fatal to himself and his passenger.
The Zenair, like many VLA and microlight aircraft, has light stick forces
and would have needed only a 25 Lbs pull on the stick to cause such a
catastrophic structural failure. High speed, light stick force and exuberant
flying make a dangerous blend.
VNO - MAXIMUM ROUGH AIR SPEED
The second safety speed to be aware of is the normal operating limit, Vno
('vee-en-owe'), which is the maximum speed the aircraft is designed to be
able to cope with in gusty or turbulent conditions without being
overstressed. It is based on an intensity of so-called sharp-edged gust
which is slightly arbitrarily assumed to be 50 feet per second, in other
words the whole aeroplane is assumed to have to transition straight from one
lump of air which is static into another which is going up at 50 feet per
second - like a high-power thermal. Putting it in simple terms, the faster
you are going when you slip from one airmass into the next, the bigger the
jerk required to accelerate the aeroplane from level flight to a 50 foot per
second climb. To hit the vertical gust at high speed gives you a hell of a
jolt, as you can imagine. Go too fast and the jolt will overstress the
aeroplane.
Of course in actual bumpy air you are usually encountering pretty much
random gusts in all directions, but the 50 foot per second model has been
found to give equivalent loads, based on the highly detailed instrumented
results of some brave RAE and NACA pilots who were sent up to explore
turbulence of increasingly severe magnitude, just after the last war. Some
of these pilots didn't come back, having found (like many glider plots
before them) that the violence inside a thunderstorm was more than their
airframes could cope with.
Vno is generally a few knots faster than Va. Again, you will find Vno stated
in most aeroplane flight manuals, and it is the bottom end of the yellow arc
(the cautionary range) on the ASI. If in doubt, use twice the stall speed.
For the pilot, the message is that unless the air conditions are smooth,
with negligible turbulence, you should not fly at a speed greater than Vno
otherwise you will risk overstressing the aeroplane if you hit a strong
gust. Slow down to give yourself a more comfortable ride, and save your
aeroplane's structure. Hitting a severe gust at high speed will cause 'g'
levels as high as pulling the stick hard back - but you may not be aware of
the danger because of the effect is an instantaneous jolt rather than a
sustained acceleration that can be felt through the seat of the pants, arms
like lead etc.
We are not talking academics here; there have been several accidents in the
last decade with structural overstress through hitting turbulence. In one
case, the pilot who was flying near vertical cliffs on a windy day appears
to have made the fatal mistake of increasing speed on encountering the
turbulence, to get away from the area of rough air - and lost his wings. The
pilot of another aircraft, flying in company with the first, chose to slow
down - and survived, but with some airframe damage.
VNE - NEVER EXCEED SPEED
The final safety speed is the most well known, the never-exceed speed Vne
('vee-en-ee'). This speed is indicated by the short red radial line and the
top end of the yellow arc on the ASI. This is the airspeed that the aircraft
is designed to cope with (usually, but not always, necessitating a dive) but
only in calm, turbulence-free conditions. The airframe is normally designed
to be able to cope with a much lesser intensity of gust at Vne, usually
equivalent to only a 25 feet/second sharp-edged gust. This is to cater for
the fact that even on an apparently turbulence-free and calm day there is
always a risk of suddenly encountering an isolated piece of mild turbulence
such as a stray thermal, or the remains of the wake turbulence from some
other aircraft which has since moved on. Encountering a 50 foot per second
gust (i.e. a severe one) at Vne would most likely cause a collapse of the
structure.
The other limiting factor is that Vne is usually the highest speed that the
aircraft is guaranteed by the designer to be free of flutter problems - he
will most likely have proven the prototype to a very slightly higher speed
than Vne (normally just 5%) to show that there is some safety margin, and to
provide for minor differences between one aeroplane and the next, the effect
of wear and changes in the friction levels in the control system with age,
and variations in the airspeed indicator errors. As high-speed flutter can
tear an airframe apart in fractions of a second, this is not a phenomenon to
be risked by ever going above Vne, outside of a proper factory test
program - or one authorised specifically by CAA, BMAA or LAA - not for
nothing do test pilots get paid to do this sort of thing - they have to wear
a parachute, and usually have jettisonable doors fitted to improve their
chances of escape.
Apart from the fact that modern light aircraft and microlights often cruise
at three or even four times their stall speeds and are therefore vulnerable
to overstressing, the streamlining of the airframe and close attention to
cockpit seals which are required to achieve this high performance causes a
further risk, which is that the pilot has fewer visible and audible cues to
warn him that he is flying fast. Flying older aircraft, you find that
increasing the airspeed much above normal cruise means a steep dive and a
roaring wind noise from the air whistling through all the leaks in the
cockpit canopy - or around the windscreen of the open cockpit. You would
have to be deaf as well as blind to miss the fact that an aeroplane like
this were being flown faster than normal - which is why in these types of
machines it is not a big deal if the ASI fails in flight. It is quite easy
to fly, manoeuvre and land these aeroplanes just using the visual and
audible cues as a measure of correct airspeed - and even if the approach is
flown a mite fast, to be on the safe side, the high drag means they won't
float very far so a safe landing can be made.
With a streamlined well-sealed aeroplane, by contrast, their higher
lift/drag ratio means that in the cruise the nose only has to drop a few
degrees to let the speed slip quickly past Vno and even past Vne. The lack
of wind noise and drafts in the cockpit makes it impossible to tell your
speed that way. Throw in a bit of bad visibility robbing the pilot of a
proper horizon, extra workload with navigation due to having to divert,
reaching behind for that flight guide or what have you, and the
possibilities for inadvertent overspeed become very real in these slippery
modern aircraft. Approach and landing with a failed ASI (all it takes is a
little water in the pitot pipework) is also much more difficult with these
machines - especially if they haven't got very effective flaps. The more
powerful the flaps, the more they reduce the lift/drag ratio which in turn
means that the change in glide angle becomes much greater (more perceptible)
for a given change in speed.
CONCLUSION
Fly too slowly and you may stall - fly too fast and there are equal or
greater perils. To fly safely, understand your aircraft's flight envelope
and speed limitations and, with modern slippery aeroplanes in particular,
the importance of taking into account turbulence when deciding your cruise
speed. If the ride feels uncomfortable, you are probably going too fast for
the conditions.
----- Original Message -----
From: "K Dilks" <kevin.dilks@liwest.at>
Sent: Thursday, October 30, 2008 2:41 PM
Subject: Zenith601-List: The UK LAA view on the Dutch XL
>
> Hope these links settle some minds out there.
>
> Cant wait to start building !
>
> http://www.lightaircraftassociation.co.uk/engineering/ch601%20web.pdf
>
>
> http://www.lightaircraftassociation.co.uk/engineering/vno%20mag%20article.pdf
>
> --------
> Austria ...guess where I work!
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=211245#211245
----- Original Message -----
From: "Paul Mulwitz" <psm@att.net>
Sent: Sunday, November 02, 2008 2:24 PM
Subject: RE: Zenith601-List: Re: Zenair Europe's comments on the Dutch
accident and grounding
>
> Hi David,
>
> Let me take a try at answering your question.
>
> I did my best to research and determine the best kit plane I could find
> when I decided I wanted to build one. I wanted a stable design that had a
> good reputation for safety and other qualities that also met the LSA
> limits. I particularly wanted a plane designed by a talented and
> accomplished designer. I determined the Zodiac XL met all my criteria
> nicely.
>
> After working on my XL kit for a year or so, I learned the design was
> indeed not at all stable. It was being changed on a nearly daily basis.
> The changes were being made by apparently inexperienced engineers who
> didn't know or care about the design principles held by the original
> designer - things like no solid rivets being used. They were trying to
> meet the new consensus standard for LSA which was still evolving when I
> thought the design was stable.
>
> Then the XLs started falling out of the sky for no apparent reason. In
> two years I heard of 4 different planes that suffered wing separations in
> what seemed like gentle flight - straight and level at apparently pattern
> speeds or normal cruise speeds. This led to numerous speculations by both
> qualified and unqualified people about why the failures had occurred and
> included at least one complete NTSB investigation that resulted in a
> worthless report.
>
> So I, for one, am frustrated about the question of whether or not there is
> a fatal design flaw in the XL. It seems there is enough smoke to indicate
> a real fire, but nobody seems to be able to pin the problem down.
>
> Now along comes a government engineer who announces he has found a fatal
> load bearing flaw in the XL design and then immediately goes on extended
> vacation so nobody can discuss it with him. The XL gets grounded in
> several countries. I figure we have one of two cases. The Dutch engineer
> was mistaken and no flaw was really found or indeed a real flaw was found
> but not announced to the world. In either case I anxiously await the
> results of this event.
>
> I suppose there are other builders nearing first flight or already flying
> who would really like for this question to get a final resolution.
> Hopefully, a design fix that actually fixes the problem will also be
> forthcoming.
>
> So yes, I am taking this event a little personally. I make no apology for
> this reaction.
>
> Best regards,
>
> Paul
> XL getting close
>
>
> At 10:25 AM 11/2/2008, you wrote:
>>Now after reading all these replies don't you guys see how personally you
>>are taking this whole thing? Your planes are not grounded, your not being
>>investigated, so why all the commotion and emotions? I could understand if
>>the FAA grounded all 601XL's in the US but that is not the case.
>>
>>Try remaining unemotional, non-speculative and just wait for the findings
>>of
>>the CAA.
>>
>>
>>David M.
>
>
>
Message 23
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| Subject: | Re: Zenith-List: XL grounded in Spain |
I'm beginning to think I'll find the simplest, cheapest experimental I can
find, even if nobody has built one in years, and list my aircraft under that
type.
--
=============================================
I like "The Magic Carpet Special"
--------
Brady McCormick
Poulsbo, WA
www.magnificentmachine.com
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=211912#211912
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